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RCAHD Epidemiology Surveillance Report

May 2023
A Communicable Diseases Update for providers in
Alleghany, Botetourt, Covington, Craig, Roanoke City and County, and Salem
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To optimally protect the community’s health, Virginia’s healthcare professionals and laboratories are required to report over 70 conditions to the Virginia Department of Health (VDH).

This newsletter provides timely updates for our local partners in public health about reportable conditions in the Roanoke City and Alleghany Health Districts (RCAHD). This issue reflects disease activity reported through March 30, 2023.
In this issue:
  • Summary of reportable diseases through March 2023
  • RCAHD Spotlight on Vector-Borne Illness
Summary of Reportable Diseases
Overview
  • There were no notable communicable disease concerns in March. Unfortunately, invasive Group A strep (17 RCAHD cases from January through the end of March) continues to be a significant local challenge as it is across the country.

Respiratory illnesses
  • Currently both COVID-19 activity and influenza activity are at low levels in our communities. Omicron variant XBB.1.5 and related variant XBB.1.16 remain the predominantly circulating strains. 

Rabies
  • Of the 57 investigations for potential exposure to rabies, 49 investigations involved domestic animals. Post-exposure prophylaxis was recommended in 15 cases. Of eight animals tested, rabies was confirmed in three cases, all skunks.

Reportable Sexually Transmitted Infections
  • We remain concerned about high levels of STI activity in our communities. Note: Through our ongoing quality assurance data review process, we identified several quality concerns including some duplicate reports. Current numbers now reflect reviewed and reconciled STI data.

(Fields with 1-4 cases have been suppressed):
Spotlight: Vector-Borne Illness
As the weather continues to improve in Southwestern Virginia, we encourage residents to take steps to protect themselves from vector-borne diseases.
 
In 2022, we received reports of 14 vector-borne diseases (excluding cases of Lyme disease) in our RCAHD localities. These included two cases of neuro-invasive West Nile virus caused by mosquitoes, as well as tick-borne diseases ehrlichiosis and Rocky Mountain Spotted Fever. 

Lyme disease reporting has changed over the years so it can be difficult to interpret trends. In 2022, case definitions were adopted that take now endemicity into account. Because Virginia is considered a high-incidence jurisdiction, the following definitions are used for surveillance purposes:
 
Suspect - A case that meets presumptive laboratory evidence
  • Positive IgG immunoblot, interpreted according to established criteria, without positive or equivocal first-tier screening assay.

Probable - A case that meets confirmatory laboratory evidence
  • Isolation of B. burgdorferi sensu stricto or B. mayonii in culture, OR
  • Detection of B. burgdorferi sensu stricto or B. mayonii in a clinical specimen by a B. burgdorferi group-specific nucleic acid amplification test (NAAT) assay, OR
  • Detection of B. burgdorferi group-specific antigens by immunohistochemical assay on biopsy or autopsy tissues, OR
  • Positive serologic tests in a two-tier or equivalent format, including:
  • Standard two-tier test (STTT): a positive or equivocal first-tier screening assay, often an enzyme immunoassay [EIA] or immunofluorescence assay [IFA] for immunoglobulin M (IgM), immunoglobulin G (IgG), or a combination of immunoglobulins, followed by a concordant positive IgM or IgG immunoblot interpreted according to established criteria, OR
  • Modified two-tier test (MTTT): positive or equivocal first-tier screen, followed by a different, sequential positive or equivocal EIA in lieu of an immunoblot as a second-tier test.

Confirmed - N/A

A 10-year review of investigations of reported Lyme disease is shown in the graph below. Please note that many reported cases do not meet case definitions. 
Although more than 15 different types of ticks have been found in Virginia, the two common ticks of particular concern are: 
·      the black-legged tick, which transmits Lyme disease
·      the Lonestar tick, found in suburban areas at lower levels of elevation such as ours, which transmits ehrlichiosis and can cause red meat allergies (alpha gal).  
 
Please encourage your clients/ patients to reduce the risk of vector-borne disease by using insect repellents, avoiding prime feeding times (dawn/ dusk) and high-risk environments (e.g., brush/ long grass), and performing tick checks with prompt tick removal.
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